Get ready to pinch yourself: The number of adults in the U.S. who own a tablet computer — of any persuasion, mind you — just about doubled from last year’s final holiday selloff period through the first few weeks of the New Year. That’s according to surveys conducted by the Pew Research Center over the past few months.

Pew ran three surveys between mid-Nov. and mid-Jan., surveying over 5,000 people in all, and found that the number of adult-age tablet owners leapt from 10% on Dec. 21 to 19% by Jan. 15. What’s more, Pew says you can apply those percentages to e-book readers (like the Kindle and Nook) as well — they surged from 10% to 19% within precisely the same timeframe.

Combine the two figures and Pew says the number of Americans who own one of these devices leapt from 18% in Dec. to 29% in Jan. Yep, nearly a third of all adults in this country can now lay claim to a tablet or e-reading device.

Pew calls the results “striking,” noting ownership from the middle of 2011 into the fall didn’t change much for tablet and e-readers. The holidays were always bound to see a platform sales boost, especially with this year’s massive tablet markdowns (RIM’s Blackberry PlayBook in particular) and Amazon’s $199 Kindle Fire entering the market, but it sounds like even Pew didn’t expect these numbers.

Some other interesting takeaways: Pew found that the number of male and female adults in the U.S. who own a tablet computer leapt from 6% (males) and 4% (females) in November 2010 to 19% (for both genders) in mid-January 2012. The figures for e-readers are notably different — from 6% (males) and 6% (females) in November 2010 to 16% (males) and 21% (females) by mid-January 2012.

Tablet ownership also has a pretty steep higher-education curve: Where tablet ownership among those who had from “some high school” to “some college” ranged from 5% to 18%, it nearly doubles to 31% among college graduates (it’s roughly the same for e-readers).